Ideal Lipstick color depends on skin tone, warm-cool, intensity, fair, medium, dark, undertone (yellow, orange, olive, etc).
Medium skins usually mostly tan when they go in the sun (because they've got melanin) while fair skin will mostly burn and not tan. With darker skin you can use darker lipstick: a wine lipstick if you have a fair skin will look way too strong.
A good way to know if your warm or cold is to use gold or silver jewelry next to your face. If you look better with gold earings, you've got a warm skin tone. Usually, its obvious which one looks better.
If you look almost as good in one or the other, you have a neutral skin color with a bit of pink and yellow (that's my skin color). Though neutral colors usually are not exactly neutral, they have a tendency to be a bit more on one side, cool or warm, or the other.
Mine is a medium skin tone, apricot, a warm to neutral skin color with an orange undertone. This means I shouldn't use any lipstick with cool undertones, but warm colors like copper, mocha, coral, berry looks real good on me.
A good way to find out more is just to go to a department store cosmetic department; they'll be happy to tell you exactly what you need. You don't even need to buy anything, though if you spend 30 minutes of their time, it would be a nice gesture :-).